I suppose you did try System Restore, before all this?
And check the Events log for clues as to what exactly is failing?
And it is also handy to have the free 'power tool' Process Explorer running, because a lot of times programmes don't appear to be open they are actually running but looking for something they can't find. PE has handy properties sheets for each process, which can help you track down what is really going on.
Also, some stuff that one takes for granted in XPPro only works for the Administrator in safe mode, on Home (the Security tabs on properties sheets for example), so it's worth trying any installing and uninstalling experiments from safe mode.
(I never could find why my IE 8 just says 'connecting' for ages though.)
Good luck,
S